Are you sure this is only an eliminator?
Fight-News writes:
Nashiro may be better skilled with good counterpunching, but Kono's tremendous physical power and advantageous physique cannot be denied because of his latest impressive performance. The winner and new WBA champ will be obliged to face the victor of an encounter between the interim ruler Rafael Concepción and Jorge Arce which also takes place on the same day (though there is a time difference between Mexico and Japan).
On the WBA-page, it is also listed as a title fight.